Amphistegina
Searched as Amphistegina antillana. The Paleobiology Database treats Amphistegina as the accepted name.
Amphistegina is a genus of foraminiferal protists included in the Rotaliida with a stratigraphic range extending from the Eocene to recent and a cosmopolitan distribution. The test is an asymmetrically biconvex trochospiral that may be bi-involute or partially evolute on the spiral side. Chambers are numerous, broad. and low, strongly curved back at the periphery to form chamber prolongations. The umbilical side is stellate, like that of Asterigerina, and has a distinct umbilical plug. The wall is calcareous, optically radial; the surface finely perforate and smooth overall. The periphery angular to carinate (keeled); the aperture an interiomarginal slit on the umbilical side, bordered by a lip.

Carlos Natário · CC BY-SA 4.0 · via Wikipedia/Commons. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.
On record
Recorded, not inferred- Sits inside
- AmphisteginidaePBDB
- Diet
- carnivorePBDB
- Life habit
- semi-infaunalPBDB, for Foraminifera
- Motility
- stationaryPBDB, for Rotaliina
- Environment
- outer shelf,marinePBDB, for Rotaliina
Time the record covers
At most 4.4 million years on record.
The one occurrence read is dated to somewhere between 15.98 Mya and 11.63 Mya, which is a dating window rather than a span.
1 occurrence of Amphistegina on record, most of them in the Miocene. The Paleobiology Database records this as a living group, and the chart stops with its fossils rather than at the present. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.
When
1 occurrences- Miocene100%
These are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. More on what this infers.
Found in
1 formation
Loading coastlines…
The named rock units Amphistegina has been recovered from, largest first. Drawn where the rock is now, not where it formed.
Amphistegina and its relatives
MioceneWhere Amphistegina and its relatives were recorded in the Miocene.
Found in the same rock
943 taxa- Elphidium105 sites
- Cibicidoides93 sites
- Foraminifera84 sites
- Cibicides83 sites
- Quinqueloculina70 sites
- Bolivina61 sites
- Textularia59 sites
- Operculina53 sites
- Discorbinella48 sites
- Lenticulina44 sites
- Heterostegina37 sites
- Heterolepa34 sites
- Uvigerina31 sites
- Lagena29 sites
- Ammonia27 sites
- Reussella25 sites
- Triloculina25 sites
- Globocassidulina23 sites
- Mesophyllum23 sites
- Cancris22 sites
- Elphidium advenum22 sites
- Melonis22 sites
- Nonionoides22 sites
- Rotalinoides22 sites
The Paleobiology Database records 514 sites for Amphistegina, and this reads 240 of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.
This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.
Entered from
1 referenceEach of the 1 occurrence read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. Each entry links to doi.org. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.
Media and terms
Media content2
Picture of Amphistegina
- Source
- Wikipedia/Commons
- Credit
- Carlos Natário
- Licence
- CC BY-SA 4.0
- Commercial use
- the licence allows it
3D model
- Source
- Sketchfab
- Credit
- BelangerForamLab
- Licence
- CC Attribution-NonCommercial
- Commercial use
- the licence does not allow it
Smithsonian Open Access and MorphoSource were not reached for this taxon, so this list is what the others held rather than everything there is.
The description on this site
- Licence
- CC BY-SA 4.0
This is what the site found, which is not the same as what exists.
Keep going
What may have been alongside itAmphisteginidae through timeFormations of the MioceneThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. d'Orbigny 1826